Added RSA/OAEP implementation.

src/rsa/rsa_i31_oaep_encrypt.c

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+/* see bearssl_rsa.h */
+size_t
+br_rsa_i31_oaep_encrypt(
+	const br_prng_class **rnd, const br_hash_class *dig,
+	const void *label, size_t label_len,
+	const br_rsa_public_key *pk,
+	void *dst, size_t dst_max_len,
+	const void *src, size_t src_len)
+{
+	size_t dlen;
+
+	dlen = br_rsa_oaep_pad(rnd, dig, label, label_len,
+		pk, dst, dst_max_len, src, src_len);
+	if (dlen == 0) {
+		return 0;
+	}
+	return dlen & -(size_t)br_rsa_i31_public(dst, dlen, pk);
+}